By extending the lactation by up to six months, both the environmental and climate impact of the livestock production may be reduced, whereas productivity and animal welfare potentially improve.
The research, published in the Journal of Dairy Science, shows that milk quality is not affected negatively - contrary to previous fears.
Previous studies are, however, old, and do not take modern livestock production into consideration, said assistant professor Nina Aagaard Poulsen from the Department of Food Science at Aarhus University.
Higher protein and fat contents
Within the context of the research project REPROLAC (Extended lactation in dairy production in favor of climate, animal welfare and productivity) she and a number of colleagues have joined forces with representatives from the dairy industry to clarify all aspects of the production method - including the effect on milk quality.
A PhD student from the Department of Food Science has been affiliated with the project, the efforts of which include a comparison of milk samples from different stages of lactation - focusing specifically on taste and the properties making milk suitable for cheese production.
As expected, milk yield decreased over time, however, the contents of protein and fat increased.
“Our investigations thus show that the cheese-making properties of milk improve during lactation,” Aagaard Poulsen said.
No negative effect on taste
The researchers have used a professional taste panel to investigate whether the extended lactation strategy affects the taste of the milk.
Previous investigations indicated that milk from cows in extended lactation may have an undesirable and salty taste.
Milk from cows in extended lactation contains more fat and protein, and this was reflected in the taste panel evaluation. Panel participants said the milk was more creamy, and there was no negative impact on milk taste.
Good sensory quality and cheesemaking properties in milk from Holstein cows managed for an 18-month calving interval
Authors: G.M. Maciel, N.A. Poulsen, M.K. Larsen, U. Kidmose, C. Gaillard, J. Sehested, L.B. Larsen
Journal of Dairy Science, 2016